code: def testNone(self):
      sequence0 = None
      sequence1 = [3, 4, 5]
      sequence2 = None
      sequence3 = [3, 3, 4, 5]
      sequence4 = None
  
      identity = lambda x: int(x)
      times3 = lambda x: int(3 * x)
      times4 = lambda x: int(4 * x)
      times5 = lambda x: int(5 * x)
      times6 = lambda x: int(6 * x)
  
      expectedValues = [
          (9, None, [3], None, None, None),
          (12, None, [4], None, None, None),
          (15, None, [5], None, [3, 3], None),
          (20, None, None, None, [4], None),
          (25, None, None, None, [5], None),
      ]
  
      i = 0
      for data in groupby2(
          sequence0,
          identity,
          sequence1,
          times3,
          sequence2,
          times4,
          sequence3,
          times5,
          sequence4,
          times6,
      ):
          self.assertEqual(data[0], expectedValues[i][0])
          for j in xrange(1, len(data)):
              temp = list(data[j]) if data[j] else data[j]
              self.assertEqual(temp, expectedValues[i][j])
          i += 1
  
file_path: nupic-legacy/tests/unit/nupic/support/group_by_test.py
imports: import unittest
  from nupic.support.group_by import groupby2
label_desc: Use image node_id 6 for calling the GroupByTest obj's underlying member method code with example usage: obj.testNone() without return types